The dangers of the current political moment in the West — with its polarization, harsh rhetoric and growing hostility toward cosmopolitanism — are evident to historians and economists alike. But which group sees the situation as more grave? I suspect it is historians, and it is worth considering why.

To be sure, some of the disgruntlement of historians stems from their political orientation. Historians are relatively left-wing, so it is no surprise that they are hostile to an “alt-right” shift in the political discourse. During the 2016 campaign, the group Historians Against Trump received widespread publicity.

More fundamentally, however, historians stress the importance of contingency, that things really could have gone another way. The decisions of a solitary assassin or the outcome of a single battle can shift the course of history. Particular leadership decisions might have avoided or limited World War I. Or what if the Germans had not, in 1917, put Lenin on a train back into Russia? The Bolshevik Revolution might have been avoided and probably the entire course of history would have been different. A shrewder President Paul von Hindenburg might have prevented the rise of Adolf Hitler.